Research led by the University of Michigan shows that it is possible to detect early to late-stage melanoma skin cancer through a blood test that detects circulating tumor cells in the blood.

As well as showing potential for cancer detection, the researchers showed the test can also be used to find out if tumor cells remain after treatment has ended.

Using microfluidics technology, the OncoBean platform was previously developed by Sunitha Nagrath, a professor in chemical engineering at the University of Michigan, and colleagues to test for circulating tumor cells present in the blood. In the new study, published in Advanced NanoBiomed Research, Nagrath and colleagues tested a melanoma-specific version of the OncoBean technology.

Almost 100,000 melanomas are diagnosed each year in the U.S. While it can be treated by surgery and other therapies if caught early, the prognosis once it has started to spread around the body is poor making early diagnosis important.

Standard surgical biopsy can be used to diagnose melanoma, but liquid biopsy from blood and plasma is easy and less invasive for patients. “While applicable to a variety of circulating markers, circulating tumor cells (CTCs) have emerged as a metastatic precursor and also known to have molecular information about the tumor,” write the authors.

“In spite of major efforts and obvious potential of using CTCs, all existing CTC assays including the only FDA-cleared CTC platform, CellSearch, are not recommended for use in melanoma diagnosis because of low sensitivity and inconsistent results.”

Nagrath and colleagues are seeking to change that with the melanoma-specific version of their microfluidic platform MelanoBean. In this study, they showed that the device is able to detect CTCs from stage I to IV in a group of 45 melanoma patients. CTC clusters were also observed in more than 15% of the patients, similar to those seen in previous studies of other cancers, and numbers of CTCs detected went down significantly following surgical treatment.

The CTCs the team recovered from the patients underwent qRT-PCR to scan for melanoma associated genes and the researchers were able to pick up a molecular signature for the tumors.

“This is the first comprehensive study of circulating tumor cells—or CTCs—to evaluate the efficacy of surgery using microfluidic systems in melanoma, including changes in the number of CTCs, CTC cluster configuration, and gene expression profiling,” said first author, Yoon-Tae Kang, also based at the University of Michigan.

“CTCs have the potential to pinpoint treatment resistance and recurrence, and can be a valuable biomarker to non-invasively monitor for disease progression,” added senior author Nagrath.

While this work shows promise, the next steps for this device are to validate the accuracy in a larger cohort of patients.